<?php
/*****************************************************************
 * Fusion.Board
 *
 * @author                Denis Wrobel
 * @license               http://www.gnu.org/licenses/gpl-3.0.html
 * @version               0.1
 *
 *****************************************************************/

if( !defined( 'IN_SCRIPT' ) )
{
    die( 'Go Away!' );
}


/*
 * This is a PHP library that handles calling reCAPTCHA.
 *    - Documentation and latest version
 *          http://recaptcha.net/plugins/php/
 *    - Get a reCAPTCHA API Key
 *          http://recaptcha.net/api/getkey
 *    - Discussion group
 *          http://groups.google.com/group/recaptcha
 *
 * Copyright (c) 2007 reCAPTCHA -- http://recaptcha.net
 * AUTHORS:
 *   Mike Crawford
 *   Ben Maurer
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

/**
 * The reCAPTCHA server URL's
 */
define( 'RECAPTCHA_API_SERVER', 'http://api.recaptcha.net' );
define( 'RECAPTCHA_API_SECURE_SERVER', 'https://api-secure.recaptcha.net' );
define( 'RECAPTCHA_VERIFY_SERVER', 'api-verify.recaptcha.net');
define( 'PUBKEY', '6Lf3lr0SAAAAADU480xbHIOo4KWPl8tcLGVeckOG ' );
define( 'PRIVKEY', '6Lf3lr0SAAAAAF9771Q4tCvWCjrf-UBNXu3JFVGu ' );

/**
 * A ReCaptchaResponse is returned from recaptcha_check_answer()
 */
class ReCaptchaResponse
{
    public $is_valid;
    public $error;
}

class ReCaptcha
{
    /**
     * Encodes the given data into a query string format
     * @param $data - array of string elements to be encoded
     * @return string - encoded request
     */
    function _recaptcha_qsencode( $data )
    {
        $req = '';
        foreach ( $data as $key => $value )
        {
            $req .= $key . '=' . urlencode( stripslashes( $value ) ) . '&';
        }
        
        // Cut the last '&'
        $req = substr( $req, 0, strlen( $req ) - 1 );
        return $req;
    }
    
    /**
     * Submits an HTTP POST to a reCAPTCHA server
     * @param string $host
     * @param string $path
     * @param array $data
     * @param int port
     * @return array response
     */
    public function _recaptcha_http_post( $host, $path, $data, $port = 80 )
    {
        $req = $this->_recaptcha_qsencode ( $data );
    
        $http_request  = "POST $path HTTP/1.0\r\n";
        $http_request .= "Host: $host\r\n";
        $http_request .= "Content-Type: application/x-www-form-urlencoded;\r\n";
        $http_request .= "Content-Length: " . strlen( $req ) . "\r\n";
        $http_request .= "User-Agent: reCAPTCHA/PHP\r\n";
        $http_request .= "\r\n";
        $http_request .= $req;
    
        $response = '';
        
        if( false == ( $fs = @fsockopen( $host, $port, $errno, $errstr, 10 ) ) )
        {
            die ('Could not open socket to ReCaptcha server');
        }
    
        fwrite( $fs, $http_request );
    
        while ( !feof( $fs ) )
        {
            $response .= fgets( $fs, 1160 ); // One TCP-IP packet
        }
        
        fclose( $fs );
        $response = explode( "\r\n\r\n", $response, 2 );
    
        return $response;
    }
    
    /**
     * Gets the challenge HTML (javascript and non-javascript version).
     * This is called from the browser, and the resulting reCAPTCHA HTML widget
     * is embedded within the HTML form it was called from.
     * @param string $pubkey A public key for reCAPTCHA
     * @param string $error The error given by reCAPTCHA (optional, default is null)
     * @param boolean $use_ssl Should the request be made over ssl? (optional, default is false)
    
     * @return string - The HTML to be embedded in the user's form.
     */
    public function recaptcha_get_html( $error = null, $use_ssl = false )
    {
        $pubkey = PUBKEY;
        
        if ($pubkey == null || $pubkey == '')
        {
            return 'To use reCAPTCHA you must get an API key from <a href="http://recaptcha.net/api/getkey">http://recaptcha.net/api/getkey</a>';
        }
                
        if ( $use_ssl )
        {
            $server = RECAPTCHA_API_SECURE_SERVER;
        }
        else
        {
            $server = RECAPTCHA_API_SERVER;
        }
        
        $errorpart = '';
        if ( $error )
        {
            $errorpart = '&amp;error=' . $error;
        }
        
        return '
        <script type="text/javascript">
            var RecaptchaOptions = {
               theme : \'clean\'
            };
        </script>
        <script type="text/javascript" src="'. $server . '/challenge?k=' . $pubkey . $errorpart . '"></script>
        <noscript>
            <iframe src="' . $server . '/noscript?k=' . $pubkey . $errorpart . '" height="300" width="500" frameborder="0"></iframe><br/>
            <textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
            <input type="hidden" name="recaptcha_response_field" value="manual_challenge"/>
        </noscript>';
    }
    
    /**
      * Calls an HTTP POST function to verify if the user's guess was correct
      * @param string $privkey
      * @param string $remoteip
      * @param string $challenge
      * @param string $response
      * @param array $extra_params an array of extra variables to post to the server
      * @return ReCaptchaResponse
      */
    public function recaptcha_check_answer( $remoteip, $challenge, $response, $extra_params = array() )
    {
        global $error;
        
        $privkey = PRIVKEY;
        if ($privkey == null || $privkey == '')
        {
            return 'To use reCAPTCHA you must get an API key from <a href="http://recaptcha.net/api/getkey">http://recaptcha.net/api/getkey</a>';
        }
    
        if ($remoteip == null || $remoteip == '')
        {
            $error->scriptError( 'For security reasons, you must pass the remote ip to reCAPTCHA' );
        }
    
        //discard spam submissions
        if ($challenge == null || strlen( $challenge ) == 0 || $response == null || strlen( $response ) == 0)
        {
            $recaptcha_response = new ReCaptchaResponse();
            $recaptcha_response->is_valid = false;
            $recaptcha_response->error = 'incorrect-captcha-sol';
                    
            return $recaptcha_response;
        }
    
        $response = $this->_recaptcha_http_post( RECAPTCHA_VERIFY_SERVER, '/verify',
                                                array('privatekey' => $privkey,
                                                      'remoteip' => $remoteip,
                                                      'challenge' => $challenge,
                                                      'response' => $response ) + $extra_params );
    
        $answers = explode ( "\n", $response[1] );
        $recaptcha_response = new ReCaptchaResponse();
    
        if( trim( $answers[0] ) == 'true' )
        {
            $recaptcha_response->is_valid = true;
        }
        else
        {
            $recaptcha_response->is_valid = false;
            $recaptcha_response->error = $answers[1];
        }
        
        return $recaptcha_response;
    }
}